That might seem obvious, but according to the National Heart, Lung, and Blood Institute, many people take a "wait and see" attitude when they experience heart attack symptoms because they don't recognize the signs of a heart attack or they attribute the symptoms to another problem. In fact, the NHLBI says that most heart attack victims wait two hours or more after symptoms begin before seeking treatment, and this delay can result in death or permanent damage to the heart.

The NHLBI says that despite the popular image of a heart attack -- someone suddenly clutching his or her chest and falling over -- most heart attacks begin slowly, as mild pain or discomfort in the chest.

According to the American Heart Association, some of the most common warning signs of a heart attack include:

Chest discomfort: Most heart attacks involve discomfort in the center of the chest that lasts for more than a few minutes, or goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain.

Discomfort in other areas of the upper body: Can include pain or discomfort in one or both arms, the back, neck, jaw, or stomach.

Shortness of breath: Often comes along with chest discomfort. But it also can occur before chest discomfort.

Other symptoms: May include breaking out in a cold sweat, nausea, or light-headedness.

The AHA urges anyone experiencing these symptoms to seek medical attention as soon as possible. In fact, the AHA and NHLBI joined forces last year to publicize the importance of not only recognizing heart attack warning signs, but also seeking medical aid as soon as possible.

The Act in Time program aims to increase people's awareness of heart attacks and the importance of calling 911 immediately at the onset of heart attack symptoms.

A Mexican photojournalist who left the state he worked in because of threats was among five people found shot to death in a Mexico City apartment this weekend, officials and press freedom advocacy groups said.